Ultra-Small, Rail-to-Rail I/O with Disable, Single-/Dual-Supply, Low-Power Op Amps MAX4245/MAX4246/ MAX4247. Features. General Description

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1 General Description The MAX4245/MAX4246/ family of low-cost op amps offer rail-to-rail inputs and outputs, draw only 32µA of quiescent current, and operate from a single +2.5V to +5.5V supply. For additional power conservation, the MAX4245/ offer a low-power shutdown mode that reduces supply current to 5nA, and puts the amplifiers outputs in a high-impedance state. These devices are unity-gain stable with a 1MHz gain-bandwidth prod uct driving capacitive loads up to 47pF. The MAX4245/MAX4246/ family is specified from -4 C to +125 C, making them suitable for use in a variety of harsh environments. The MAX4245 single amplifier is available in ultra-small 6-pin SC7 and spacesaving 6-pin SOT23 packages. The MAX4246 dual amplifier is available in 8-pin SOT23, SO, and µmax packages. The dual amplifier comes in a tiny 1-pin µmax package. Applications Portable Communications Single-Supply Zero-Crossing Detectors Instruments and Terminals Electronic Ignition Modules Infrared Receivers Sensor-Signal Detection Selector Guide PART AMPLIFIERS PER PACKAGE SHUTDOWN MODE MAX4245AXT 1 Yes MAX4245AUT 1 Yes MAX4246AKA 2 No MAX4246ASA 2 No MAX4246AUA 2 No AUB 2 Yes Features Rail-to-Rail Input and Output Voltage Swing 5nA (max) Shutdown Mode (MAX4245/) 32µA (typ) Quiescent Current Per Amplifier Single +2.5V to +5.5V Supply Voltage Range 11dB Open-Loop Gain with 2kΩ Load.1% THD with 1kΩ Load Unity-Gain Stable up to C LOAD = 47pF No Phase Inversion for Overdriven Inputs Available in Space-Saving Packages 6-Pin SC7 or 6-Pin SOT23 (MAX4245) 8-Pin SOT23/SO or 8-Pin µmax (MAX4246) 1-Pin µmax () Ordering Information PART TEMP RANGE P- PACKAGE +Denotes a lead(pb)-free/rohs-compliant package. T = Tape and reel. TOP MARK MAX4245AXT+T -4 C to +125 C 6 SC7 AAZ MAX4245AUT+T -4 C to +125 C 6 SOT23 AAUB MAX4246AKA+T -4 C to +125 C 8 SOT23 AA MAX4246ASA+T -4 C to +125 C 8 SO MAX4246AUA+T -4 C to +125 C 8 µmax AUB+T -4 C to +125 C 1 µmax Pin Configurations TOP VIEW MAX V DD V SS SHDN A B- A- A MAX V DD B - SC7-6/SOT23-6 V SS 4 5 B+ SOT23-8/µMAX-8 μmax is a registered trademark of Maxim Integrated Products, Inc. Pin Configurations continued at end of datat sheet ; Rev 3; 5/14

2 Absolute Maximum Ratings Power-Supply Voltage (V DD to V SS )...-.3V to +6V All Other Pins...(V SS -.3V) to (V DD +.3V) Output Short-Circuit Duration ( shorted to V SS or V DD )... Continuous Continuous Power Dissipation (T A = +7 C) 6-Pin SC7 (derate 3.1mW/ C above +7 C)...245mW 6-Pin SOT23 (derate 8.7mW/ C above +7 C)...695mW 8-Pin SO (derate 5.9mW/ C above +7 C)...471mW 8-Pin SOT23 (derate 9.1mW/ C above +7 C)...727mW 8-Pin µmax (derate 4.5mW/ C above +7 C)...362mW 1-Pin µmax (derate 5.6mW/ C above +7 C)...444mW Operating Temperature Range C to +125 C Junction Temperature C Storage Temperature Range C to +16 C Lead Temperature (soldering, 1s)...+3 C Soldering Temperature (reflow) C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Electrical Characteristics (V DD = +2.7V, V SS = V, V CM = V, V = V DD /2, R L connected from to V DD /2, SHDN_ = V DD (MAX4245/ only), T A = +25 C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS M TYP MAX UNITS Supply Voltage Range V DD Inferred from PSRR test V V DD = +2.7V Supply Current (Per Amplifier) I DD V DD = +5.5V Supply Current in Shutdown I SHDN_ SHDN_ = V SS (Note 2).5.5 µa Input Offset Voltage V OS V SS -.1V V CM V DD +.1V ±.4 ±1.5 mv Input Bias Current I B V SS -.1V V CM V DD +.1V ±1 ±5 na Input Offset Current I OS V SS -.1V V CM V DD +.1V ±1 ±6 na Input Resistance R V + - V - 1mV 4 kω Input Common-Mode Voltage Range V CM Inferred from CMRR test V SS -.1 V DD +.1 V Common-Mode Rejection Ratio CMRR V SS -.1V V CM V DD +.1V 65 8 db Power-Supply Rejection Ratio PSRR 2.5V V DD 5.5V 75 9 db Large-Signal Voltage Gain A V V SS +.5V V V DD -.5V, R L = 1kΩ V SS +.2V V V DD -.2V, Specified as R L Output Voltage Swing High V = 1kΩ 1 OH mv V DD - V 35 6 Specified as R L Output Voltage Swing Low V = 1kΩ 1 OL mv V - V SS 3 6 Output Short-Circuit Current I (SC) V DD = +5.V Output Leakage Current in Shutdown I (SH) Device in Shutdown Mode (SHDN_ = V SS ), V SS V V DD (Note 2) Sourcing 11 Sinking 3 µa db ma ±.1 ±.5 µa SHDN_ Logic Low V IL (Note 2).3 x V DD V SHDN_ Logic High V IH (Note 2).7 x V DD V SHDN_ Input Current I L /I H V SS SHDN_ V DD (Note 2).5 5 na Maxim Integrated 2

3 Electrical Characteristics (continued) (V DD = +2.7V, V SS = V, V CM = V, V = V DD /2, R L connected from to V DD /2, SHDN_ = V DD (MAX4245/ only), T A = +25 C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS M TYP MAX UNITS Gain-Bandwidth Product GBW 1. MHz Phase Margin Φ M 7 degrees Gain Margin G M 2 db Slew Rate SR.4 V/µs Input Voltage-Noise Density e n f = 1kHz 52 nv/ Hz Input Current-Noise Density i n f = 1kHz.1 pa/ Hz Capacitive-Load Stability C LOAD A V = 1 (Note 3) 47 pf Shutdown Delay Time t (SH) (Note 2) 3 µs Enable Delay Time t (EN) (Note 2) 4 µs Power-On Time t ON 4 µs Input Capacitance C 2.5 pf Total Harmonic Distortion (V DD = +2.7V, V SS = V, V CM = V, V = V DD /2, R L connected from to V DD /2, SHDN_ = V DD (MAX4245/ only), T A = -4 C to +125 C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS M TYP MAX UNITS Supply Voltage Range V DD Inferred from PSRR test V Supply Current (Per Amplifier) I DD V DD = +2.7V 8 µa Supply Current in Shutdown I SHDN_ SHDN_ = V SS (Note 2) 1 µa Input Offset Voltage V OS V SS V CM V DD (Note 4) ±3. mv Input Offset Voltage Drift TCV OS V SS V CM V DD (Note 4) ±2 µv/ C Input Bias Current I B V SS V CM V DD (Note 4) ±1 na Input Offset Current I OS V SS V CM V DD (Note 4) ±1 na Input Common-Mode Voltage Range V CM Inferred from CMRR test (Note 4) V SS V DD V Common-Mode Rejection Ratio CMRR V SS V CM V DD (Note 4) 6 db Power-Supply Rejection Ratio PSRR 2.5V V DD 5.5V 7 db Large-Signal Voltage Gain A V V SS +.2V V V DD -.2V, 85 db Output Voltage Swing High V OH Specified as V DD - V, 9 mv Output Voltage Swing Low V OL Specified as V - V SS, 9 mv Output Leakage Current in Shutdown THD I (SH) f = 1kHz, V = 2V P-P, A V = +1, V DD = +5.V, Load = 1kΩ to V DD /2 Device in Shutdown Mode (SHDN_ = V SS ), V SS V V DD (Note 3).1 % Settling Time to.1% t S V = 4V step, V DD = +5.V, A V = +1 1 µs Electrical Characteristics ±1. µa Maxim Integrated 3

4 Electrical Characteristics (continued) (V DD = +2.7V, V SS = V, V CM = V, V = V DD /2, R L connected from to V DD /2, SHDN_ = V DD (MAX4245/ only), T A = +25 C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS M TYP MAX UNITS SHDN_ Logic Low V IL (Note 2).3 x V DD V SHDN_ Logic High V IH (Note 2).7 x V DD V SHDN_ Input Current I L /I H V SS SHDN_ V DD (Notes 2, 3) 1 na Note 1: Specifications are 1% tested at T A = +25 C. All temperature limits are guaranteed by design. Note 2: Shutdown mode is only available in MAX4245 and. Note 3: Guaranteed by design, not production tested. Note 4: For -4 C to +85 C, Input Common-Mode Range is V SS -.1V V CM V DD +.1V. Typical Operating Characteristics (V DD = 2.7V, V SS = V CM = V, V = V DD /2, no load, T A = +25 C, unless otherwise noted.) 5 45 SUPPLY CURRENT PER AMPLIFIER vs. SUPPLY VOLTAGE T A = +125 C MAX4245 toc MAX4245/ SHUTDOWN SUPPLY CURRENT PER AMPLIFIER vs. TEMPERATURE MAX4245 toc2 6 5 PUT OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE V DD = 2.5V T A = +125 C T A = +85 C MAX4245 toc3 IDD (µa) T A = +85 C T A = +25 C T A = -4 C ISHDN (na) VOS (µv) T A = +25 C T A = -4 C V DD (V) TEMPERATURE ( C) V CM (V) VOS (mv) PUT OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE V DD = 5.5V T A = +125 C T A = +85 C T A = +25 C MAX4245 toc4 VOS (µv) PUT OFFSET VOLTAGE vs. TEMPERATURE V DD = 2.5V MAX4245 toc5 IBIAS (na) PUT BIAS CURRENT vs. COMMON-MODE VOLTAGE V DD = 5.5V T A = +125 C T A = +85 C T A = -4 C MAX4245 toc V CM (V) T A = -4 C TEMPERATURE ( C) V DD = 5.5V T A = +25 C V CM (V) Maxim Integrated 4

5 Typical Operating Characteristics (V DD = 2.7V, V SS = V CM = V, V = V DD /2, no load, T A = +25 C, unless otherwise noted.) ISOURCE (ma) PUT SOURCE CURRENT vs. PUT VOLTAGE V DD = 2.5V V DD = 5.5V MAX4245 toc7 ISK (ma) PUT SK CURRENT vs. PUT VOLTAGE V DD = 5.5V V DD = 2.5V MAX4245 toc8 VDD - V (mv) PUT SWG HIGH vs. TEMPERATURE R L = 1kΩ MAX4245 toc V (V) V (V) TEMPERATURE ( C) V - VSS (mv) PUT SWG LOW vs. TEMPERATURE R L = 1kΩ MAX4245 toc1 CROSSTALK (db) CROSSTALK vs. FREQUENCY MAX4245 toc11 PSRR (db) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY MAX4245 toc TEMPERATURE ( C) , FREQUENCY (khz) , FREQUENCY (khz) THD + N (%) TOTAL HARMONIC DISTORTION PLUS NOISE vs. PUT FREQUENCY MAX4245 toc13 R L = 1kΩ A V = +1 V = 2V P-P V DD = 5.V THD + N (%) TOTAL HARMONIC DISTORTION PLUS NOISE vs. AMPLITUDE R L = 1kΩ A V = +1 f = 1kHz V DD = 5.V MAX4245 toc14 GA (db) GA AND PHASE vs. FREQUENCY MAX4245 toc15 9 NO LOAD 3 GA PHASE PHASE (deg) , 1, PUT FREQUENCY (Hz) PUT VOLTAGE (V P-P ) , FREQUENCY (khz) Maxim Integrated 5

6 Typical Operating Characteristics (continued) (V DD = 2.7V, V SS = V CM = V, V = V DD /2, no load, T A = +25 C, unless otherwise noted.) 8 GA AND PHASE vs. FREQUENCY MAX4245 toc16 2kΩ 47pF 9 SMALL-SIGNAL TRANSIENT RESPONSE (NONVERTG) MAX4245 toc mV/div GA (db) 4 2 GA PHASE PHASE (deg) 2mV/div , FREQUENCY (khz) 4µs/div SMALL-SIGNAL TRANSIENT RESPONSE (VERTG) MAX4245 toc18 LARGE-SIGNAL TRANSIENT RESPONSE (NONVERTG) V DD = 5V MAX4245 toc19 2mV/div 2mV/div 4µs/div 4µs/div LARGE-SIGNAL TRANSIENT RESPONSE (VERTG) V DD = 5V MAX4245 toc2 4µs/div Maxim Integrated 6

7 Pin Description P MAX4245 MAX4246 NAME FUNCTION 1 + Noninverting Input V SS Ground or Negative Supply 3 - Inverting Input 4 Amplifier Output 5 SHDN Shutdown V DD Positive Supply 1 1 A Amplifier Output Channel A 2 2 A- Inverting Input Channel A 3 3 A+ Noninverting Input Channel A 5 7 B+ Noninverting Input Channel B 6 8 B- Inverting Input Channel B 7 9 B Amplifier Output Channel B 5 SHDNA Shutdown Channel A 6 SHDNB Shutdown Channel B R3 V DD R3 V DD R3 = R1 R2 R3 = R1 R2 R1 R2 R1 R2 Figure 1a. Minimizing Offset Error Due to Input Bias Current (Noninverting) Detailed Description Rail-to-Rail Input Stage The MAX4245/MAX4246/ have rail-to-rail input and output stages that are specifically designed for lowvoltage, single-supply operation. The input stage consists of composite NPN and PNP differential stages, which operate together to provide a common-mode range extending to both supply rails. The crossover region of these two pairs occurs halfway between V DD and V SS. The input offset voltage is typically ±4µV. Lowoperating supply voltage, low supply current and rail-torail outputs make this family of operational amplifiers an excellent choice for precision or general-purpose, lowvoltage, battery-powered systems. Figure 1b. Minimizing Offset Error Due to Input Bias Current (Inverting) Since the input stage consists of NPN and PNP pairs, the input bias current changes polarity as the common-mode voltage passes through the crossover region. Match the effective impedance seen by each input to reduce the offset error caused by input bias currents flowing through external source impedance (Figures 1a and 1b). The combination of high-source impedance plus input capacitance (amplifier input capacitance plus stray capacitance) creates a parasitic pole that can produce an underdamped signal response. Reducing input capacitance or placing a small capacitor across the feedback resistor improves response in this case. The MAX4245/MAX4246/ family s inputs are protected from large differential input voltages by internal 5.3kΩ series resistors and back-to-back triple-diode stacks across the inputs (Figure 2). For differential-input voltages Maxim Integrated 7

8 - 5.3kΩ + 5.3kΩ Figure 2. Input Protection Circuit much less than 2.1V (triple-diode drop), input resistance is typically 4MΩ. For differential voltages greater than 2.1V, input resistance is around 1.6kΩ, and the input bias current can be approximated by the following equation: I B = (V DIFF - 2.1V)/1.6kΩ In the region where the differential input voltage approaches 2.1V, the input resistance decreases exponentially from 4MΩ to 1.6kΩ as the diodes begin to conduct. It follows that the bias current increases with the same curve. In unity-gain configuration, high slew-rate input signals may capacitively couple to the output through the triplediode stacks. Rail-to-Rail Output Stage The MAX4245/MAX4246/ can drive a 2kΩ load and still typically swing within 35mV of the supply rails. Figure 3 shows the output voltage swing of the MAX4245 configured with A V = -1V/V. Applications Information Power-Supply Considerations The MAX4245/MAX4246/ operate from a single +2.5V to +5.5V supply (or dual ±1.25V to ±2.75V supplies) and consume only 32µA of supply current per amplifier. A 9dB power-supply rejection ratio allows the amplifiers to be powered directly off a decaying battery voltage, simplifying design and extending battery life. Power-Up The MAX4245/MAX4246/ output typically settles within 4µs after power-up. Figure 4 shows the output voltage on power-up and power-down. Shutdown Mode The MAX4245/ feature a low-power shutdown mode. When SHDN_ is pulled low, the supply current drops to 5nA per amplifier, the amplifier is disabled, and Figure 3. Rail-to-Rail Input/Output Voltage Range V DD 4µs/div 1µs/div Figure 4. Power-Up/Power-Down Waveform the output enters a high-impedance state. Pulling SHDN_ high enables the amplifier. Figure 5 shows the MAX4245/ s shutdown waveform. Due to the output leakage currents of three-state devices and the small internal pullup current for SHDN_, do not leave SHDN_ open/high-impedance. Leaving SHDN_ open may result in indeterminate logic levels, and could adversely affect op amp operation. The logic threshold for SHDN_ is referred to V SS. When using dual supplies, pull SHDN_ to V SS, not GND, to shut down the op amp. Driving Capacitive Loads The MAX4245/MAX4246/ are unity-gain stable for loads up to 47pF. Applications that require greater capacitive drive capability should use an isolation resistor Maxim Integrated 8

9 SHDN R ISO R L CL Figure 6a. Using a Resistor to Isolate a Capacitive Load from the Op Amp 4µs/div Figure 5. Shutdown Waveform between the output and the capacitive load (Figures 6a, 6b, 6c). Note that this alternative results in a loss of gain accuracy because R ISO forms a voltage divider with the R LOAD. Power-Supply Bypassing and Layout The MAX4245/MAX4246/ family operates from either a single +2.5V to +5.5V supply or dual ±1.25V to ±2.75V supplies. For single-supply operation, bypass the power supply with a 1nF capacitor to V SS (in this case GND). For dual-supply operation, both the V DD and the V SS supplies should be bypassed to ground with separate 1nF capacitors. Good PC board layout techniques optimize performance by decreasing the amount of stray capacitance at the op amp?s inputs and output. To decrease stray capacitance, minimize trace lengths and widths by placing external components as close to the device as possible. Use surface-mount components when possible. Pin Configurations (continued) R ISO = Ω C L = 22pF 1µs/div 1mV/div 1mV/div Figure 6b. Pulse Response Without Isolating Resistor R ISO = 1Ω C L = 22pF 1mV/div TOP VIEW A V DD 1mV/div A- 2 9 B 1µs/div A+ 3 8 B- Figure 6c. Pulse Response With Isolating Resistor V SS 4 7 B+ Chip Information PROCESS: BiCMOS SHDNA 5 6 SHDNB µmax Maxim Integrated 9

10 Package Information For the latest package outline information and land patterns (footprints), go to Note that a +, #, or - in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. LAND PATTERN NO. 6 SOT23 U SC7 X6SN SOT23 K SO S µmax U µmax U Maxim Integrated 1

11 Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 5/1 Initial release 2 11/11 Added lead-free data to Ordering Information /14 Updated the General Description. 1 For pricing, delivery, and ordering information, please contact Maxim Direct at , or visit Maxim Integrated s website at Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. 214 Maxim Integrated Products, Inc. 11